1. Field of the Invention
The invention is directed to a drive device for the road wheels of a vehicle with a stationary housing in which a rotatably drivable differential housing with an axle differential gear unit is rotatably mounted by differential bearings, typically two driveshafts being rotatably drivable by the differential housing, a driving gear wheel being arranged on the two driveshafts in each instance so as to be fixed with respect to rotation relative to the latter. The driving gear wheels meshingly engage by oppositely directed helical teeth with driven gear wheels for driving road wheels of the vehicle and generate axial forces directed toward the center of the axle differential gear unit, with thrust bearing arrangements for supporting these axial forces, these thrust bearing arrangements being in turn supported at a structural component part of the drive device.
2. Description of the Related Art
In a drive device of the type mentioned above, it is known to support the axial forces of the driving gear wheels directed toward the center of the axle differential at parts of the housing that project radially between the driving wheels and the differential housing until closely adjacent to the driveshafts and have an axial guide and a radial supporting surface for the thrust bearing arrangements.
If the helix angle of the helical toothing is to be large so that higher outputs can be transmitted, there will also be an increase in the axial forces generated by the driving gear wheels and directed to the center of the axle differential and which must be supported via the thrust bearing arrangements at the parts of the housing. This requires a larger bearing arrangement and a more stable design of the parts of the housing and, therefore, a larger installation space. However, enlargement in that axial direction is impossible because the installation space is limited by the rims of the road wheels, by the tire clearance for the latter and by the differential bearings and because spacer disks must be arranged between the support points for the thrust bearing arrangements for the exact positioning of the thrust bearing arrangements.